Well, there is a typo in that code that I just noticed. I edited my previous post to fix it.

However, it looks like SexyCooldown re-shows its frames every time a cooldown starts, so that code won't work anyway. Rather than hiding and showing individual frames, it will probably work better to re-parent them all to the CombatHider frame and just hide and show that, so the hidden/shown state of the inidividual frames doesn't matter: